Banded Houndshark: Triakis scyllium

Family: Triakidae

Common name(s)

Banded Houndshark.

Identification

Body slender. Snout fairly short and rounded. Upper labial furrows slightly longer than lower. Small, visible spiracle behind eye. First dorsal fin origin slightly posterior to pectoral fin free rear tip. Posterior edge of first dorsal almost vertical. Second dorsal fin larger than anal fin. Second dorsal origin slightly posterior to pelvic fin free rear tip. Lower caudal lobe indistinct but with a small curved apex. Dorsal coloration brown with dusky saddles/bands and small, irregular scattered black spots. Bands fade in adults; sometimes becoming absent.

Size

Maximum length 150cm. Size at birth 18-20cm.

Habitat

A temperate/sub-tropical species inhabiting shallow muddy or sandy bays, estuaries, eelgrass beds, and rocky reefs. Usually found near the bottom close inshore.

Distribution

Banded houndsharks are found in the northwest pacific from southern Russia, Japan, Koreas, China, and Taiwan.

Conservation Status

LEAST CONCERN

The banded houndshark is relatively widespread and common throughout its range. Threats include bycatch in gillnet and setnets. Although this shark is not a target species, it is sometimes still eaten. It is also known to occur in rocky, un-fished, nearshore areas off Japan, providing it with some refuges. This species is also commonly found in aquariums in China and Japan. Although few data are available on the species’ population, it is common and there is no evidence to suggest population declines. Based on the current information, this shark is listed as Least Concern.

Citations and References
Ebert, D.A., Tanaka, S. & Nakaya, K. 2009. Triakis scyllium. The IUCN Red List of Threatened Species 2009: e.T161395A5413845. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161395A5413845.en. Downloaded on 03 November 2020.

Reproduction

An aplacental viviparous species (without a yolk-sac placenta). 10-24 pups per litter.

Diet

Predates mainly on small fishes and crustaceans, plus some other invertebrates.

Behavior

Banded houndsharks enter estuaries to feed. Sometimes found alone but will congregate in large numbers where food is readily available e.g. around fishing boats where bycatch is discarded.

Reaction to divers

Usually very shy and difficult to approach unless habituated to the presence of divers.

Diving logistics

Although it is possible to randomly encounter banded houndsharks while reef diving in Japan, sightings are rare and generally unrewarding. However, over a period of years, the banded houndshark population in southwestern Chiba (south of Tokyo) has been the focus of a concerted effort to develop a commercial shark feed. This was initially done to distract them from nearby fishing boats because they were damaging nets. Now completely habituated to the presence of divers, the houndsharks are extremely easy to approach as they tumble over one another in their pursuit of the bait.
Big fish expeditions runs yearly Japanese shark diving safaris for English speaking divers that includes multiple dives with the houndsharks, plus dives with many other endemic Japanese shark species.